Two points are the focus of this effort: (1) The variety of consequences of the mu- and delta-opioid receptor agonists/endogenous ligands within localized regions of the central nervous system could indicate (a) degeneracy of those two receptor subtypes or (b) the existence of endogenous ligands other than enkephalins and endorphins. (2) The peripheral (P-) opioid receptor system which mediates inflammation- associated antinocicepition appears to represent a unique type of opioid receptor; alternatively, it may actually comprise multiple receptor subtypes. Mor et al. (Paris) obtained an antiserum to dermorphin and used it to address point (1) by using it to recover an undefined material from a HPLC column. Our efforts to try to confirm that report have been hampered due to the absence of a suitable antiserum. Because dermorphin is a D-amino acid-containing peptide, we decided to temporarily expand the scope of the investigation to the more general problem of looking for brain peptides which may contain a D-amino acid. An antiserum to an analogue of NMDA was recently characterized (P. Petrusz et al., UNC-CH) and shown to be capable of recognizing a small D-amino acid-containing peptide; while that peptide material is being purified, we are applying Dr. Petrusz's technique to obtain an antiserum suitable for dermorphin/deltorphin. Groups in Germany and Brazil have reported on the apparently paradoxial sensory pain receptors (point 2). As Ferreira's group (in Sao Paulo) has reported that regulation of cyclic-GMP is a consequence of the transduction phenomena controlled by P-receptor(s), a collaborative effort has been initialized to employ the frog skin opioid peptides in an attempt to develop a better understanding of peripheral opioid receptor characteristics.